Reverse Filtering

In course of Internet filtering research  enumerating what is blocked where, using what technology and why  it is necessary to account for all lot of ambiguous data and the level of complexity involved in making authoritative determinations of filtering technology, levels and content. One such item to take into account is reverse filtering. Reverse filtering occurs when its the requested web server that blocks itself from processing requests for specific countries as opposed to what is generally presumes  that countries or institutions block access to a particular website via filtering technology, firewall or some such network device configured to block access to the requested web site. When reverse filtering occurs it be just assumed that the requested content is blocked by the country/technology being enumerated when in fact the web site is deny itself to users from particular countries.
One such site godaddy.com does exactly that. After reading a few postings by users in certain countries being unable to access the service  and confirming this with proxy servers I email godaddy.com to find out what was up. Here is their response:

We are currently unable to process transactions originating from the following countries:

In addition, the United States Government asks that we do not conduct business with these nations:

Cuba
Iran
Iraq
Libya
North Korea
Sudan
Syria

If your credit card is issued from an establishment located within one of these countries, or if you reside in one of these countries, you will not be able to complete a purchase from our website or access our network. We apologize for any inconvenience that this may cause.